Possible Causes

• Fuse
• Wiring, terminals or connectors
• HCU
• ABS module

Fig 1: Antilock Braking System (ABS) Module Connector - C135

Courtesy of FORD MOTOR COMPANY

Harness Side

1. H1: CHECK THE VEHICLE BATTERY AND CHARGING SYSTEM 
   • Verify the vehicle battery and charging system are operating correctly. Refer to Inspection and Verification in the Charging System General Information article, Charging System Diagnosis and Testing.
   • Are the battery and charging system operating correctly? 

   Yes	No
   Go to  H2.	FOLLOW the diagnostic repair directions as instructed in the Charging System General Information article, Charging System Diagnosis and Testing.

2. H2: VERIFY ALL WIRING CONNECTIONS 
   • Ignition OFF.
     NOTE: The battery must be removed to access the ABS module electrical connector.
   • Remove the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • ABS Module connector disconnected. (C135)
   • Using a good light source, inspect all disconnected electrical connectors for the following:
     • corrosion - install new connector or terminal and clean the module pins
     • damaged or bent pins - install new terminals or pins
     • pushed-out pins - install new pins as necessary
     • spread terminals - install new terminals as necessary
   • Using a suitable mating terminal, check each connector terminal for deformed or enlarged contacts by comparing the mating terminal's fit between each of the following pins:
     • C135-1
     • C135-14
   • Is connector free of terminal corrosion, pushed-out terminals and spread terminals? 

   Yes	No
   Go to  H3.	REPAIR the affected terminal. Refer to the Connector Repair Procedures article for schematic and connector information.

3. H3: CHECK PUMP MOTOR OPERATION 
   • ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
   • Install the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • Ignition ON, engine OFF.
   • Access the ABS and control the PMP_MTR (MODE) PID.
   • Command the pump motor on and listen for the ABS pump motor to activate.
   • Does the ABS pump motor run for approximately 2 seconds when commanded on? 

   Yes	No
   Go to  H4.	Go to  H5.

4. H4: CHECK FOR FAULT REPEATABILITY 
   • Clear the ABS DTCs.
   • Ignition OFF.
   • Ignition ON, engine OFF.
   • Test drive the vehicle at speeds greater than 20 km/h (12 mph).
   • Ignition OFF.
   • Ignition ON, engine OFF.

     Carry out the ABS self-test.

   • Is DTC C0020:71 or C1B02:71 present? 

   Yes	No
   Go to  H7.	For all other C0020:xx, C1B02:xx and C052E:xx DTCs, Go to  H5. For all other DTCs, No fault found. GO to the ABS Module DTC Chart. If there are no DTCs present, No fault found. the system is operating correctly at this time. DISCONNECT and INSPECT the ABS module electrical connector. CLEAN or REPAIR the connector as necessary. ADDRESS the root cause of any connector or pin issues.

5. H5: CHECK THE PUMP MOTOR VOLTAGE SUPPLY TO THE ABS MODULE 
   NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
   NOTE: This step puts a load on the ABS module voltage supply circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A 9006 or 9007 headlamp bulb is an effective load.
   • Ignition OFF.
     NOTE: VERIFY BJB fuse 7 (50A) is OK. If not OK, REFER to the OEM Electrical Wiring Diagram Introduction article to identify the possible causes of the circuit short.
     NOTE: The battery must be removed to access the ABS module electrical connector.
   • Remove the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • ABS Module connector disconnected. (C135)
   • Install the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • Ignition ON, engine OFF.
   • Measure the voltage between:

     (+) Vehicle Battery	(-) Vehicle Battery
     Positive terminal	Negative terminal

   • Record the measured battery voltage.
   • Connect the load to a suitable ground connection.
   • Connect the load to each circuit before taking the voltage measurement.
   • Measure the voltage between:

     (+) ABS Module (C135) Connector, Harness Side	(-)
     Motor B+ - SBB07 (WHITE/RED) - Pin 1	Ground

   • Is the measured voltage within 0.5 volt of the recorded battery voltage? 

   Yes	No
   Go to  H6.	REPAIR the circuit.

6. H6: CHECK THE ABS MODULE GROUND CIRCUIT FOR AN OPEN 
   NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may cause damage to the connector.
   NOTE: This step puts a load on the ABS module voltage supply circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A 9006 or 9007 headlamp bulb is an effective load.
   • Ignition OFF.
   • Connect the load to a suitable, fused 12-volt power connection.
   • Connect the load to the circuit before taking the voltage measurement.
   • Measure the voltage between:

     (+) ABS Module (C135) Connector, Harness Side	(-)
     GND - GD122 (BLACK) - Pin 14	Ground

   • Is each voltage drop less than 0.5 volt? 

   Yes	No
   Go to  H7.	REPAIR the circuit.

7. H7: VERIFY ALL WIRING CONNECTIONS 
   NOTE: The battery must be removed to access the ABS module electrical connector.
   • Remove the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • ABS Module connector disconnected. (C135) (if not previously disconnected)
   • Using a good light source, inspect all disconnected electrical connectors for the following:
     • corrosion - install new connector or terminal and clean the module pins
     • damaged or bent pins - install new terminals or pins
     • pushed-out pins - install new pins as necessary
     • spread terminals - install new terminals as necessary
   • Are the connectors free of corrosion, damaged pins, bent pins, pushed-out pins and spread terminals? 

   Yes	No
   Go to  H8.	REPAIR the connector or terminals. Refer to the Connector Repair Procedures article for schematic and connector information.

8. H8: CHECK FOR APPLICABLE SERVICE ARTICLES 
   • CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.
   • Do any applicable service articles exist? 

   Yes	No
   DISCONTINUE this test and FOLLOW the service article instructions.	Go to  H12.

9. H9: VERIFY ALL WIRING CONNECTIONS 
   NOTE: The battery must be removed to access the ABS module electrical connector.
   • Remove the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
   • ABS Module connector disconnected. (C135)
   • Using a good light source, inspect all disconnected electrical connectors for the following:
     • corrosion - install new connector or terminal and clean the module pins
     • damaged or bent pins - install new terminals or pins
     • pushed-out pins - install new pins as necessary
     • spread terminals - install new terminals as necessary
   • Are the connectors free of corrosion, damaged pins, bent pins, pushed-out pins and spread terminals? 

   Yes	No
   Go to  H10.	REPAIR the connector or terminals. Refer to the Connector Repair Procedures article for schematic and connector information.

10. H10: CHECK FOR APPLICABLE SERVICE ARTICLES 
    • CHECK OASIS for any service articles: TSB, GSB, SSM or FSA.
    • Do any applicable service articles exist? 

    Yes	No
    DISCONTINUE this test and FOLLOW the service article instructions.	For DTC C0020:13 and C0020:16, Go to  H12. For DTC C0020:11, C0020:12 and C0020:71, Go to  H11.

11. H11: CHECK FOR CORRECT ABS MODULE AND HCU OPERATION 
    • ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
    • Install the battery. Refer to the appropriate procedure in the Battery, Mounting and Cables article.
    • Connect the battery negative cable. Refer to the General Procedure in the Battery, Mounting and Cables article.
    • Operate the system and determine if the concern is still present.
    • Is the concern still present? 

    Yes	No
    INSTALL a new ABS module. INSTALL a new HCU and ABS module assembly. REFER to the Anti-Lock Brake System (ABS) and Stability Control article. ORDER a replacement ABS module and HCU assembly and INCLUDE the RVC on the form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.

12. H12: CHECK FOR CORRECT ABS MODULE OPERATION 
    • ABS Module connector connected. (C135) Make sure the connector seats and latches correctly.
    • Connect the battery negative cable. Refer to the General Procedure in the Battery, Mounting and Cables article.
    • Operate the system and determine if the concern is still present.
    • Is the concern still present? 

    Yes	No
    INSTALL a new ABS module. INSTALL a new ABS module. REFER to the Anti-Lock Brake System (ABS) and Stability Control article. ORDER a replacement ABS module and INCLUDE the RVC on the form. If this is a Ford paid repair, INCLUDE the RVC on the warranty claim form.	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.